Circuit interrupter



Nov 24, 1953 Filed May 18. 1950 Gas Evolving Material WITNESSES:

H. RAWLINS 2,660,647

CIRCUIT INTERRUPTER 3 Sheets-Sheet 3 INVENTOR Herbert L. Rowlins, deceased ,by Charlotte M. Ruwlins,Adminis1rurrix.

Patented Nov. 24, 1953 UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER Application May 18, 1950, Serial No. 162,666

18 Claims. 1

This invention relates to circuit interrupters, in general, and more particularly to arc-extinguishing structures therefor.

A general object of this invention is to provide an improved circuit interrupter, particularly one of the air-break type, in which are extinction is more readily effected and in which more effective use of the gas blast is achieved.

Another object is to provide an improved circuit interrupter, particularly one of the spaced plate type, in which the flow of arc gases is more effectively stored and directed against the arc stream to effect the extinction thereof.

A further object is to provide an improved arc chute of the spaced-plate type in which a storage chamber is utilized to collect the evolved gas so that the stored gas may be forced through the arc stream at or near a current zero on the alternating current wave.

Another object is to provide an improved piston arrangement for assisting in the interruption of low current arcs in the above types of interrupting structures, such that the operating mechanism therefor is simple, compact and will not in any manner interfere with rapid opening motion of the contact structure.

Another object is to provide an improved arc chute of the spaced plate type, in which perforations of novel configuration are provided in the several plates to more effectively deionize the arc stream.

Further objects and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

Figure 1 is a vertical sectional view through an arc chute and piston arrangement embodying my invention, the contact structure being shown in the closed circuit position;

Fig. 2 is a vertical sectional view taken along the line II-II of Fig. 1, looking in the direction of the arrows;

Fig. 3 is a side elevational view of one of the plates, and the spacers therefor, utilized in the arc chute of Fig. 1;

Fig. 4 is a vertical sectional view taken along the line IV-IV of Fig. 3, looking in the direction of the arrows;

Fig. 5 is a modified type of plate and spacer arrangement which may be substituted for the 2 plate spacer arrangement of Figs. 3 and 4 in the arc chute of Fig. 1;

Fig. 6 shows another modified type of plate and spacer arrangement which may be substituted for the plate and spacer arrangement of Figs. 3 and 4 in the arc chute of Fig. 1;

Fig. 7 is a graph showing the volt-ampere interrupting characteristics of the arc chute of Fig. l; and

Fig. 8' is a modified type of arc chute, generally similar to the one shown in Fig. 1, but longer, and having an improved arc horn construction.

Referring to the drawings, and more particularly to Fig. 1 thereof, the reference character I generally designates a circuit interrupter, particularly one of the air-break type, utilizing a plurality of spaced perforated gas-evolving plates 2. The configuration of the plates 2 is more clearly shown in Fig. 3. Referring to Fig. 3, it will be observed that each plate 2 has a perforation 3 provided therethrough of pear-shaped or tear-drop configuration. The plates 2 are of generally rectangular shape.

The plates 2 are assembled into grooves 4 provided on the opposed inner side walls of a pair of side support plates 5. Spacing the plates 2 apart are a plurality of cooperating pairs of gas evolving spacer plates 6, having a configuration more clearly shown in Fig. 3 of the drawings. As shown in Fig. 3, each pair of spacer plates 6 forms a constriction impeding the upward flow of arc gases out of the interrupter l.

The interrupter i provides a storage region 9 at the lower end thereof in which the evolved gases resulting from the arc contacting the gasevolving plates 2 and spacers 6 may be stored. These stored gases are utilized at or near a current zero on the alternating current wave in passing back upwardly through the arc stream established between the stationary contact l0 and the moving contact H. The are is extinguished by the stored gases passing upwardly between the plates 2 through the constricted portion 1 and upwardly out of the top of the interrupter I.

As mentioned, the plates 2 and the spacers 6 are preferably composed of a suitable gasevolving material such as horn fiber, or of a suitable urea resin with an alpha cellulose filler. The arc, drawn between the stationary and the moving contacts 10, II will react upon the gasevolving plates 2, and closely adjacent spacer plates 6, to evolve a large quantity of gas. Because of the presence of the constriction I, this evolved gas, largely generated near the peak of the alternating current wave, will pass downwardly into the storage region 9, at the lower end of the interrupter l. During its passage downwardly intothe storage region 9, this evolved gas will be cooled and deionized by its flow through the passages I2 provided between the plate portions l3 at the lower ends of the plates 2.

This gas is stored in the storage region 9 until near a current zero on the alternating current wave, at which time the generation of evolved gas diminishes because of the lower instantane ous values of arcing current. At this time, the stored gas from the storage region 9 will passback upwardly through the passages [2' between the lower plate portions l3, and through the arc stream itself, the arc at this time being positioned at the upper ends M of the perforations 3- provided in the plates 2. The stored gas, in passing upwardly through the arc, forces the sameagainst the upper ends M of the apertures 3 and effects the extinction thereof by gas blast action.

Fig. '7 shows generally the volt-ampere interrupting characteristics of a self-generated type of interrupter of the type shown in Fig. 1 without a puffer. From this curve it will be apparent that during relatively low amperage values of interrupted current the amount of gas generated will be relatively small, and hence the voltage which the interrupter can interrupt will be relatively small.

However, as the amperage of the interrupted current increases, the amount of gas evolved from the plates 2 and the gas-evolving spacers 6 increases rapidly, so' that the kilovolts interrupted will be greatly increased. It will be obvious, of

course, that points falling in' the region A above the curve l5 denote values of current and voltage which the self-generated interrupter I will not interrupt, whereas points falling in the region B below the curve I5 indicate points which the interrupter I can safely interrupt.

Because the interrupting ability of the interrupter l islrelatively low near the lower end of the current range, it is'advisable to utilize a supplementary form of auxiliary gas supplying device, either in the form of a compressed gas jet, or a puffer, as indicated by the reference character ll of Fig. 1. The piston arrangement or puffer I1 includes a piston I8 movable within an operating cylinder I! being spring-biased to the'right, as shown in Fig. l, by a battery of compression springs 20. Preferably the piston I8 is guided by a piston rod 2| passing through a guide aperture 22 provided in a head 23.

The piston I8 is charged during the closing operation, against the biasing action exerted by the compression springs 20, by a push-rod or plunger 24; An insulating operating rod 26 has a bridge 2-! secured thereto, the bridge 21 having the plunger 24 and the moving contact I I secured to the outer ends thereof. Consequently, rightward movement of the operating rod 26, as viewed in Fig. 1, as permitted by the operating mechanism, which forms no part of the invention, draws an arc between the contacts l0 and H through the several perforations 3; and simultaneously releases the piston I8 so that the latter is'free to move under the biasing action exerted by the compression springs 20'.

During the interruption of relatively high Iii) 4 values of current, where the volume of evolved gas is considerable, the gas pressure within the storage region 9, which communicates through an opening 28 into the piston chamber 29, may be high enough to stall rightward working motion of the piston Hi. When the piston I8 is thus stalled by the high pressure of the gas during high current interruption, the volume of the piston chamber 29 must be added to the storage volume 9 in considering the total volume V available during such interruption for the storage of evolved gas.

During the interruption of low currents, on the other hand, when the evolved gas is relatively small, then the piston M will move to the right, as viewed in Fig. 1, being acted upon by the biasing force exerted by the compression springs 20. The rightward movement of the piston [8 during such low current interruption will not only serve to diminish the storage volume V available for accumulated evolved gas, but will also serve to provide a supplementary flow of gas upwardly through the arc stream established between the stationary and moving contacts I0, I l.

Preferably the ratio of A/V should be in the order of .001 to .025, where A is the discharge area and V is the arc chamber volume. The discharge area A would be the summation of the cross-sectional areas of the constrictions 1 taken through the interrupter l. The are chamber storage volume V would be the storage region 9 plus any volume provided by the piston cham-' ber 29.

In one arrangement that was tried, eleven plates 2 and the spacers 6 therefor each hada:

plate thickness of 5 of an inch. The cross-sec tion of the constriction I was x /g inch and the eleven plates 2 utilized gave a total discharge area of 1.17 square inches. The total storage volume was 50' cubic inches without a puffer. Utilizing the puffer 11, an 8' inch di-' ameter piston l-8 was employed having a 4" inch stroke. Later a 5-inch diameter piston [8 was employed having a 6 /2 inch long stroke.

Later tests on another model'of the'typeshown in Fig. 1 utilized inch thick plates 2' with the spacers 6, as before, being of an inch. In this model the cross-sectional-area of the constriction l was t; x inch, giving a total discharge" area A of 0.82 inch. In this model eight plates 2 were utilized. The storage volume V was increased to 200 cubic inches without a puffer. Another model involving eleven plates 2 was tested having the plate thickness inch, spacer thickness A inch, with the discharge area being x inch;

The total discharge area A was 0.78 squareinch. Another model utilizing thirteen plates 2 was tested, the'plates 2 having a thickness of A. inch,

spacer thickness inch and the cross section of the constriction I being 532 X inch, giving a total discharge area A of 0.7 square inch. The spacer configuration was like that of Fig. 5, de scribed hereinafter.

A final model was tested using eleven plates 2 having a inch thickness, the spacer thickness being inch, and the constriction cross-sectional area-1 being %'xinch.

Certain modifications of the plate configura tion were utilized, as set forth in Figs. 5 and'6: In Fig. 5 the aperture 30 was lengthened, and the spacers 60 were lengthened and drawn in closely adjacent to the sides of the apertures 30 so that a greater evolution of evolved gaswould be obtained; In other words, there was a greater area of gas-evolving material exposed to the arc stream.

Fig. 6 shows a arrangeiumt in which a x inch slot 3| was provided at the upper end of the aperture 3 so that during low instantaneous values of arcing current, the arc would rise upwardly into the slot 3|. The spacers 6 had the same arrangement as before.

Fig. 8 shows an interrupter 32, generally similar to the interrupter I of Fig. 1, but being longer, and having arc horns 33, 34 associated respectively with the stationary and moving contacts III, II. The other features of the interrupter 32 are the same as previously described in connection with Fig. 1, there merely being a greater number of plates 2 and the operating cylinder l9a being longer.

The function of the arcing horns 33, 34 is to permit lengthening of the are at a greater rate than separation of the contacts III, II.

From the foregoing description of the improved interrupter, it will be apparent that it provides a substantially enclosed arc chute of the self-generating type utilizing gas-evolving material for both the splitter plates 2 and the spacer plates 8. It will be observed that the evolved gas is stored in the storage region 9 and within the piston chamber 29 until near a current zero, at which time the stored gas passes upwardly through the arc stream to effect the extinction thereof.

For making the interrupter more effective at lower values of current, an auxiliary piston device or puffer I! is employed for speeding up low current interruption and for providing additional storage space during high-current interruption, at which time the piston it! will be stalled due to the relatively high gas pressure.

Although specific structures have been shown and described, it is to be clearly understood that the same were merely for the purpose of illustrating the invention, and that changes and modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the appended claims.

What is claimed as new is:

1. A circuit interrupter including a substantially enclosed arc chute, means defining a storage space adjacent one end of the arc chute, continually open venting means disposed adjacent the other end of the arc chute, a plurality of spaced gas-evolving insulating plates, means for establishing an are adjacent the gas-evolving insulating plates within the arc chute between the continually open venting means and the storage space, and the evolved gas being collected in the storage space to pass through the arc stream during low instantaneous values of arcing current to effect the extinction thereof.

2. A circuit interrupter including a substantially enclosed arc chute, means defining a storage space adjacent one end of the arc chute, continually open venting means disposed adjacent the other end of the arc chute, a plurality of spaced insulating gas-evolving plates, means for establishing an are within the arc chute adjacent the gas-evolving plates between the continually open venting means and the storage space, means defining a relatively unrestricted passage interconnecting the arcing region with the storage space, a spring-biased pufier communicating with the storage space to assist in low current interruption, and the evolved gas being freely collected in the storage space to pass through the arc stream during low instantaneous 6 values of arcing current to effect the extinction thereof.

3. A circuit interrupter including a substantially enclosed arc chute, means defining a storage space adjacent one end of the arc chute, continually open venting means disposed adjacent the other end of the arc chute, a plurality of spaced plates, means for establishing an are within the arc chute between the continually open venting means and the storage space, and the ratio of discharge area to storage space being in the range from .001 to .025.

4. A circuit interrupter including a substantially enclosed arc chute, means defining a storage space adjacent one end of the arc chute, continually open venting means disposed adjacent the other end of the arc chute, a plurality of spaced plates, means for establishing an are within the arc chute between the continually open venting means and the storage space, the spaced plates being formed of gasevolving material, and the ratio of discharge area to storage space being in the range from .001 to .025.

5. A circuit interrupter including a substantially enclosed arc chute, means defining a storage space adjacent one end of the arc chute, continually open venting means disposed adjacent the other end of the arc chute, a plurality of spaced plates, means for establishing an are within the arc chute between the continually open venting means and the storage space, a spring-biased puffer communicating with the storage space to assist in low current interruption, and the ratio of discharge area to storage space being in the range from .001 to .025.

6. A circuit interrupter including a substantially enclosed arc chute, means defining a storage space adjacent one end of the arc chute, continually open venting means disposed adjacent the other end of the arc chute, a plurality of spaced gas-evolving insulating plates, means for establishing an are adjacent the gasevolving insulating plates within the arc chute between the continually open venting means and the storage space, a plurality of pairs of spacer plates between the adjacent spaced gas-evolving plates forming constrictions therebetween and disposed between the continually open venting means and the arc-establishing means, and the evolved gas being collected in the storage space to pass through the arc stream during low instantaneous values of arcing current to effect the extinction thereof.

'7. A circuit interrupter including a substantially enclosed arc chute, means defining a storage space adjacent one end of the arc chute, continually open venting means disposed adjacent the other end of the arc chute, a plurality of spaced insulating gas-evolving plates, means for establishing an are within the arc chute adjacent the gas-evolving plates between the continually open venting means and the storage space, means defining a relatively unrestricted passage interconnecting the arcing region with the storage space, means for feeding a supplementary gas blast through the are at least during low current interruption, and the evolved gas being freely collected in the storage space to pass through the arc stream during low instantaneous values of arcing current to effect the extinction thereof.

8. A circuit interrupter including a substantially enclosed arc chute, a plurality of spaced gas-evolving perforated splitter plates, a pair acac a-'2 7 of spacer plates between adjacent splitter plates forming constrictions therebetween within: the arc chute, means. for establishing: an. arcthrough the perforations; and. a. blast. of gas effecting extinction of the. established are passing. through the: constrictions.

9: circuit interrupter including: a substantially enclosed arc? chute, a plurality of spaced gas-evolving perforated splitter. plates, a pair of spacer plates between adjacent. splitter plates forming constrictions th'erebetween within: the arc chute, means for establishing: an are through the: perforations, a blast of gas efiecting extinction of the established: are passing through the: constrictions, and the spacer plates being: formed-of a gas-evolving material;

1 0; A circuit interrupter including a substantially' enclosed arc: chute, a: plurality of spaced gasaevolving perforated splitter plates, 2; pair of laterally spaced spacer plates: between adjacent splitter plates forming constrictions therebetween within the arc chute, means for establish' ing an are through the perforations, a blast of gasefle'cting extinction of the established arc, passing through the constrictions, and narrow slots-cut at the exhaust ends oi theperforations to restrict the established are.

11. A circuit interrupter including a substantially' enclosed arc chute, means defining a storage spaceadjacent one end of the arc chute, continually open venting means disposed adjacent the other end of the arc chute, a plurality of spaced apertured gas-evolving insulating. splitter plates, means for estal'alishi'ng an arc through the apertures within the gas-evolving splitter plates between the continually open venting means and the storage space, and the evolved gas being collected in the storage space to pass through the arc stream during low instantaneous values of arcing current to effect. the extinction thereof.

12 A circuit interrupter including a substantially enclosed arc chute, means defining a storage space adjacent one end of the arc chute, continually open venting means disposed adjacent the other end of the arc chute, a pluralityof spaced plates, a plurality of pairs ofspacer plates separated laterally apart between the adjacent spaced plates forming constrictionstherebetween and disposed between the continuallyopen venting means and the arc-establishing means, means for establishing an are within the arc chute between the continually ope-n venting means and the storage space, and the ratio of discharge area to storage space being. in the range from .001 to .025.

13. A circuit interrupter including a substantially enclosed arc chute, means defining a storage space adjacent one end oi": the arc chute, continually open venting means disposed adjacent the other end of the arc chute, a plurality of spaced gas-evolving insulating plates, means for establishing an are adjacent the gas-evolving plates within the arc chute between the continually open venting. means and the storage space to evolve gas therefrom, the evolved gas being collected in the storage space, means: for diminishing the volume of the storage space during low current interruption, and the ratio of discharge area to storage space being in the range from .001 to .025.

14. A circuit interrupter including a substantially enclosed arc chute, means defining a storage space adjacent one end of the arc chute,

continually open venting means disposed adjacent the other end of the arc chute, a plurality of spaced gas-evolving insulating plates, means for establishing an arc adjacentfthegas-evolving plates within the arc chute between the continually open venting means and the storage space to evolve gas therefrom, the evolved gas being collected in the storage space, means-for diminishing the volume of the storage space during low current interruption, the ratio of discharge area to storage space being inthe range' from .001 to .025, and a plurality'oi pairs of spacer plates separated laterally apart between the adjacent spaced plates forming constrictions therebetween and disposed between the continually-open venting means and the are. establishing means.

15 A circuit interrupter including a substantially enclosed arc chute, means defining a storage space adjacent one end of the arc chute, continually open venting means disposed adjacent the other. end of the arc chute, a plurality of spaced gas-evolving perforated insulating, plates disposed between the storage space and the continually open venting means, means for establishing an are through the perforations pro:- vided by the gas-evolving spaced plates within the arc chute, and the evolved gas being collected in the storage space to pass through the arc stream during low instantaneous values of arc-- ing current to eifect the extinction thereof;

16. A circuit interrupter including a substantially enclosed arc chute, meansdefining a storage space adjacent one endof the arc chute, continually open venting means disposed adja-- cent the other end of the arc chute, a pluralityof spaced gas-evolving perforated insulating plates disposedibetween the storage space and the continually open venting means, means for establishing an are through the perforations provided by the gas-evolving spaced plates within the arc chute, the evolved gas being collected in the storage space to pass through the arc stream during low instantaneous values of arcing current to effect the extinction thereof, and a plurality of pairs of spacer plates separated laterally apart between the adjacent spaced plates forming constrictions therebetween and disposed between the continually open venting means and the arc-establishing means.

1'7. A circuit interrupter including a substan-" tial-ly enclosed arc chute, means defining a storage space adjacent one end of the arc" chute, continually open venting means disposed: adjacent the other end of the arc chute, a plurality of spaced gas-evolving perforated insulating plates disposed between the storage spaceand the continually open venting means, means for establishing an are. through the perforationsprovided by the; gas-evolving spaced plates within theare chute, the. evolved gas being. collected in the storage space to pass through the arc stream during low instantaneous, values of arcingcurrentto. eifect the. extinction thereof, and the ratio of discharge area to". storage space being" in the range from .00l to .025.

18 A circuit interrupter including. av substantially enclosed arc chute, means defining a storage space adjacent one end: of the arc chute, continually open venting means disposed adjacent the other end of the. arc chute, a plurality of spaced ga s-evolving perforated" insulating plates disposed between the storage space and the continually open venting means, means for estab- References Cited in the file of this patent UNITED STATES PATENTS Number 16 Administratria: of the estate 0) Herbert L. Number Rawlz'ns, deceased.

Name Date Slepian Jan. 5, 1932 Graves, Jr. Feb. 11, 1936 Graves, Jr. Dec. 29, 1936 Paul Aug. 19, 1941 Grosse Apr. 7, 1942 Fernier Oct. 5, 1943 Baker et a1. Apr. 4, 1944 Slepian May 23, 1944 Milliken Oct. 17, 1950 FOREIGN PATENTS Country Date Great Britain Apr. 29, 1937 

